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Physics Faculty Publications

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Articles 1861 - 1890 of 2178

Full-Text Articles in Physical Sciences and Mathematics

Debye-Series Analysis Of The First-Order Rainbow Produced In Scattering Of A Diagonally Incident Plane Wave By A Circular Cylinder, James A. Lock, Charles L. Adler Jun 1997

Debye-Series Analysis Of The First-Order Rainbow Produced In Scattering Of A Diagonally Incident Plane Wave By A Circular Cylinder, James A. Lock, Charles L. Adler

Physics Faculty Publications

We derive the Debye-series expansion of the partial-wave scattering and interior amplitudes for the interaction of a diagonally incident beam of arbitrary profile with an infinitely long homogeneous dielectric circular cylinder. We then discuss the physical interpretation of the various terms of the series. We also consider the one-internal-reflection Debye-series terms for diagonal plane-wave incidence and examine the first-order rainbow extinction transition as a function of the tilt angle of the incident plane wave. We experimentally observe the first-order rainbow extinction transition and compare our observations with the Debye-series predictions. (C) 1997 Optical Society of America.

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Degenerate Layer At Gan/Sapphire Interface: Influence On Hall-Effect Measurements, David C. Look, Richard J. Molnar Jun 1997

Degenerate Layer At Gan/Sapphire Interface: Influence On Hall-Effect Measurements, David C. Look, Richard J. Molnar

Physics Faculty Publications

Temperature-dependent Hall-effect measurements in hydride vapor phase epitaxial GaN grown on sapphire can be well fitted over the temperature range 10–400 K by assuming a thin, degenerate n-type region at the GaN/sapphire interface. This degenerate interfacial region dominates the electrical properties below 30 K, but also significantly affects those properties even at 400 K, and can cause a second, deeper donor to falsely appear in the analysis. However, by using a two-layer Hall model, the bulk mobility and carrier concentration can be accurately ascertained.

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The N-15/N-14 Isotope Fractionation In Dissociative Recombination Of N-2(+), Jane L. Fox, Aleksander B. Hać Apr 1997

The N-15/N-14 Isotope Fractionation In Dissociative Recombination Of N-2(+), Jane L. Fox, Aleksander B. Hać

Physics Faculty Publications

We have carried out Monte Carlo calculations of the velocity distributions and escape fractions for 14N and 15N released in dissociative recombination of 28N2+ and 29N2+, respectively, for a range of ion temperatures (Ti) and electron temperatures (Te) appropriate to the Martian exosphere. Separate calculations were carried out for each vibrational level of N2+ for 0≤ν≤6. We have taken into account the variation in the dissociative recombination cross section with relative velocity of the ion and electron, and the differences in the vibrational …

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Enhanced Coupling To Microsphere Resonances With Optical Fibers, A. Serpengüzel, S. Arnold, G. Griffel, James A. Lock Apr 1997

Enhanced Coupling To Microsphere Resonances With Optical Fibers, A. Serpengüzel, S. Arnold, G. Griffel, James A. Lock

Physics Faculty Publications

Morphology-dependent resonances (MDR's) of polystyrene microspheres were excited by an optical fiber coupler. For optical elimination of the air-cladding interface at the optical fiber coupler surface, the microsphere was immersed in an index-matching oil. MDR's were observed, even though the relative refractive index between the microsphere and the oil was only 1.09. The observed MDR spectra are in good agreement with the generalized Lorenz-Mie theory and the localization principle. The scattering efficiency into each MDR is estimated as a function of the impact parameter by means of generalized Lorenz-Mie theory. (C) 1997 Optical Society of America.

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Chemistry Of The Jovian Auroral Ionosphere, J. J. Perry, Y. H. Kim, Jane L. Fox, H. S. Porter Apr 1997

Chemistry Of The Jovian Auroral Ionosphere, J. J. Perry, Y. H. Kim, Jane L. Fox, H. S. Porter

Physics Faculty Publications

No abstract provided.

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A Fast Scan Submillimeter Spectroscopic Technique, Douglas T. Petkie, Thomas M. Goyette, Ryan P. A. Bettens, Sergei P. Belov, Sieghard Albert, Paul Helminger, Frank C. De Lucia Apr 1997

A Fast Scan Submillimeter Spectroscopic Technique, Douglas T. Petkie, Thomas M. Goyette, Ryan P. A. Bettens, Sergei P. Belov, Sieghard Albert, Paul Helminger, Frank C. De Lucia

Physics Faculty Publications

A new fast scan submillimeter spectroscopic technique (FASSST) has been developed which uses a voltage tunable backward wave oscillator (BWO) as a primary source of radiation, but which uses fast scan (~105 Doppler limited resolution elements/s) and optical calibration methods rather than the more traditional phase or frequency lock techniques. Among its attributes are (1) absolute frequency calibration to ~1/10 of a Doppler limited gaseous absorption linewidth (<0.1 MHz, 0.000 003 cm-1), (2) high sensitivity, and (3) the ability to measure many thousands of lines/s. Key elements which make this system possible include the excellent short term spectral purity of the …

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Microscopic Nature Of Thermally Stimulated Current And Electrical Compensation In Semi-Insulating Gaas, S. Kuisma, K. Saarinen, P. Hautojarvi, Z-Q. Fang, David C. Look Apr 1997

Microscopic Nature Of Thermally Stimulated Current And Electrical Compensation In Semi-Insulating Gaas, S. Kuisma, K. Saarinen, P. Hautojarvi, Z-Q. Fang, David C. Look

Physics Faculty Publications

No abstract provided.

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Optical And Magneto-Optical Properties Of Mnpt3 Films (Abstract), Segate Corporation, Pittsburgh, Pa, J. N. Hilfiker, Renat F. Sabirianov, Sitaram S. Jaswal, Roger D. Kirby, John A. Woollam Apr 1997

Optical And Magneto-Optical Properties Of Mnpt3 Films (Abstract), Segate Corporation, Pittsburgh, Pa, J. N. Hilfiker, Renat F. Sabirianov, Sitaram S. Jaswal, Roger D. Kirby, John A. Woollam

Physics Faculty Publications

Optically thick films of MnPt3 were prepared by magnetron sputtering onto quartz substrates. Postdeposition annealing at 850 °C resulted in highly textured (111) films with the L12 (Cu3Au) structure. MnPt3 films are ferromagnetic with a Curie temperature of 380 °C, and they show large magneto-optical effects in the visible.1,2 These films also show a high degree of long-range order. The diagonal components of the dielectric tensor were determined using variable angle spectroscopic ellipsometry measurements over the spectral range 1.2–2.4 eV. Magneto-optic Kerr rotation and ellipticity measurements were made at near normal incidence over the …

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Bifurcation Of The Equilibrium States Of A Weightless Liquid Bridge, Lev A. Slobozhanin, J. Iwan D. Alexander, Andrew Resnick Mar 1997

Bifurcation Of The Equilibrium States Of A Weightless Liquid Bridge, Lev A. Slobozhanin, J. Iwan D. Alexander, Andrew Resnick

Physics Faculty Publications

The bifurcation of the solutions of the nonlinear equilibrium problem of a weightless liquid bridge with a free surface pinned to the edges of two coaxial equidimensional circular disks is examined. The bifurcation is studied in the neighborhood of the stability boundary for axisymmetric equilibrium states with emphasis on the boundary segment corresponding to nonaxisymmetric critical perturbations. The first approximations for the shapes of the bifurcated equilibrium surfaces are obtained. The stability of the bifurcated states is then determined from the bifurcation structure. Along the maximum volume stability limit, depending on values of the system parameters, loss of stability with …

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Study Of The Crystallization Of Zeolite Naa By Quasi-Elastic Light-Scattering Spectroscopy And Electron Microscopy, Leszek Gora, Kiril A. Streletzky, Robert W. Thompson, George D.J. Phillies Mar 1997

Study Of The Crystallization Of Zeolite Naa By Quasi-Elastic Light-Scattering Spectroscopy And Electron Microscopy, Leszek Gora, Kiril A. Streletzky, Robert W. Thompson, George D.J. Phillies

Physics Faculty Publications

A study of the crystallization of the molecular sieve zeolite NaA from clear aluminosilicate solutions is reported. It was determined by powder X-ray diffraction that zeolite NaA was the only phase in the solid precipitate. The syntheses were monitored in situ by quasi-elastic light scattering spectroscopy. Characteristics of the products were examined by scanning and transmission electron microscopy. Our data show that nuclei formed from the clear aluminosilicate solution, that crystal growth occurred from the solution, that crystal growth was accelerated at elevated temperatures, and that aging the solution at room temperature before raising the synthesis temperature increased both the …

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Thermal Fluctuations In Systems With Continuous Symmetry, Ulrich Zürcher Mar 1997

Thermal Fluctuations In Systems With Continuous Symmetry, Ulrich Zürcher

Physics Faculty Publications

We investigate relaxation and thermal fluctuations in systems with continuous symmetry in arbitrary spatial dimensions. For the scalar order parameter ζ(r, t) with r∈ℛd, the deterministic relaxation is caused by hydrodynamic modes η∂ζ(r, t)/∂t= K∇2ζ(r, t). For a finite volume V, we expand the scalar field in a discrete Fourier series and then we study the behavior in the limit V→∞. We find that the second moment is well defined for dimensions d≥3, while it diverges for d=1, 2. Furthermore, we show that for d<4, the decay of the scalar field does not define an "effective" relaxation time. For dimensions d<4, these two properties suggest scale-invariant properties of the scalar field in the limit V→∞. We show that thermal fluctuations are described by fractional Brownian motion for d ≤ 3 and by ordinary Brownian motion for d ≥ 4. The spectral density of the stochastic force follows 1/f for d=1 and d=2, for d=3, and "white noise," f0 for d≥4. We find explicit representation of the equilibrium distribution of the conserved scalar field. For d≥4 it is a Gaussian distribution, while for d=1 and d=2, it is the Cauchy distribution.

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Scattering Of A Diagonally Incident Focused Gaussian Beam By An Infinitely Long Homogeneous Circular Cylinder, James A. Lock Mar 1997

Scattering Of A Diagonally Incident Focused Gaussian Beam By An Infinitely Long Homogeneous Circular Cylinder, James A. Lock

Physics Faculty Publications

I expand the radiation potential of an arbitrary monochromatic electromagnetic wave in the cylindrical coordinate eigenfunctions of the scalar Helmholtz equation. Since the resulting beam shape coefficients are found to be an inverse Fourier transform of the z component of the beam fields, the incident Gaussian beam is parameterized by a Fourier angular spectrum of plane waves. The beam's partial-wave coefficients are then obtained, as well as the scattered fields produced by the interaction of the beam with an infinitely long homogeneous circular cylinder. The fields are evaluated analytically in the far zone by the method of stationary phase, and …

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Morphology-Dependent Resonances Of An Infinitely Long Circular Cylinder Illuminated By A Diagonally Incident Plane Wave Or A Focused Gaussian Beam, James A. Lock Mar 1997

Morphology-Dependent Resonances Of An Infinitely Long Circular Cylinder Illuminated By A Diagonally Incident Plane Wave Or A Focused Gaussian Beam, James A. Lock

Physics Faculty Publications

The S matrix for scattering a diagonally incident focused Gaussian beam by an infinitely long circular cylinder is calculated, and the diagonal and off-diagonal elements of the matrix are physically interpreted. In addition, the TE and TM morphology-dependent resonances of the cylinder for plane-wave incidence are examined, and it is found that the cylinder size parameter at resonance increases as the angle of incidence of the plane wave increases. The size parameter increase is explained in terms of the heuristic model of morphology-dependent resonances. The presence of both TE and TM resonances in each of the epsilon-polarized and mu-polarized partial-wave …

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Optical Properties Of Gan Grown On Zno By Reactive Molecular Beam Epitaxy, F. Hamdani, A. Botchkarev, W. Kim, H. Morkoç, M. Yeadon, J. M. Gibson, S.-C. Y. Tsen, David J. Smith, Donald C. Reynolds, David C. Look, K. R. Evans, Cole W. Litton, William C. Mitchel, P. Hemenger Jan 1997

Optical Properties Of Gan Grown On Zno By Reactive Molecular Beam Epitaxy, F. Hamdani, A. Botchkarev, W. Kim, H. Morkoç, M. Yeadon, J. M. Gibson, S.-C. Y. Tsen, David J. Smith, Donald C. Reynolds, David C. Look, K. R. Evans, Cole W. Litton, William C. Mitchel, P. Hemenger

Physics Faculty Publications

High quality wurtzite GaN epilayers have been grown on ZnO(0001) substrates by reactive molecular beam epitaxy. Photoluminescence and reflectivity measurements point to high quality presumably due to the near match of both the crystal lattice parameter and the stacking order between GaN and ZnO. In addition, the good films lack the characteristic yellow photoluminescence band. Any misorientation of the GaN epilayer planes with respect to the ZnO substrate is not detectable with polarized reflectivity. The x-ray double crystal diffraction measurements indicate this misorientation is much smaller than those for GaN epilayers on SiC and Al2O3 . © …

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An Instantaneous Normal Mode Description Of Relaxation In Supercooled Liquids, T. Keyes, G. V. Vijayadamodar, Ulrich Zurcher Jan 1997

An Instantaneous Normal Mode Description Of Relaxation In Supercooled Liquids, T. Keyes, G. V. Vijayadamodar, Ulrich Zurcher

Physics Faculty Publications

Relaxation in supercooled liquids is formulated from the instantaneous normal modes (INM) point of view. The frequency and temperature dependence of the unstable, imaginary frequency lobe of the INM density of states, ⟨ρu(ω,T)⟩ (for simplicity we write ω instead of iω), is investigated and characterized over a broad temperature range, 10⩾T⩾0.42, in the unit density Lennard-Jones liquid. INM theories of diffusion invoke Im-ω modes descriptive of barrier crossing, but not all imaginary frequency modes fall into this category. There exists a cutoff frequency ωc such that modes with ω<ωc correspond to “shoulder potentials,” whereas the potential profiles include barrier-crossing double wells for ω>ωc. Given that only modes with ω>ωc contribute to diffusion, …

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Plateau Tank Apparatus For The Study Of Liquid Bridges, Andrew Resnick, J. Iwan D. Alexander Jan 1997

Plateau Tank Apparatus For The Study Of Liquid Bridges, Andrew Resnick, J. Iwan D. Alexander

Physics Faculty Publications

An apparatus has been constructed and used to study the equilibrium and dynamical behavior of liquid bridges under reduced effective gravity. Liquid bridges are created and manipulated using six independent computer controlled stepper motors which drive linear motion tables. The bridges are visualized with a high magnification coherent Fourier optical system and in an orthogonal view using incoherent white light. By calibrating a density hydrometer and measuring the interfacial energy between the bridge and bath, reliable Bond numbers as low as 10−4 can be created and held stable for extended periods of time. Dimensional control of the liquid bridges approaches …

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Depth Measurement Of Doped Semiconductors Using The Hall Technique, G. C. Desalvo, David C. Look, Christopher A. Bozada, J. L. Ebel Jan 1997

Depth Measurement Of Doped Semiconductors Using The Hall Technique, G. C. Desalvo, David C. Look, Christopher A. Bozada, J. L. Ebel

Physics Faculty Publications

No abstract provided.

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Identification Of Electron-Irradiation Defects In Semi-Insulating Gaas By Normalized Thermally Stimulated Current Measurements, David C. Look, Z-Q. Fang, Joseph W. Hemsky, P. Kengkan Jan 1997

Identification Of Electron-Irradiation Defects In Semi-Insulating Gaas By Normalized Thermally Stimulated Current Measurements, David C. Look, Z-Q. Fang, Joseph W. Hemsky, P. Kengkan

Physics Faculty Publications

No abstract provided.

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How Much Of The Nucleon Spin Is Carried By Glue?, Ian Balitsky, Xiangdong Ji Jan 1997

How Much Of The Nucleon Spin Is Carried By Glue?, Ian Balitsky, Xiangdong Ji

Physics Faculty Publications

We estimate in the QCD sum rule approach the amount of the nucleon spin carried by the gluon angular momentum: the sum of the gluon spin and orbital angular momenta. The result indicates that gluons contribute at least one half of the nucleon spin at the scale of 1GeV2.

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H2s Adsorption On Chromium, Chromia, And Gold/Chromia Surfaces: Photoemission Studies, J A. Rodriguez, S Chaturvedi, U Diebold, M Kuhn, J Van Ek, P S. Robbert, H Geisler, C A. Ventrice Jr Jan 1997

H2s Adsorption On Chromium, Chromia, And Gold/Chromia Surfaces: Photoemission Studies, J A. Rodriguez, S Chaturvedi, U Diebold, M Kuhn, J Van Ek, P S. Robbert, H Geisler, C A. Ventrice Jr

Physics Faculty Publications

The reaction of H2S with chromium, chromia, and Au/chromia films grown on a Pt(111) crystal has been investigated using synchrotron-based high-resolution photoemission spectroscopy. At 300 K, H2S completely decomposes on polycrystalline chromium producing a chemisorbed layer of S that attenuates the Cr 3d valence features. No evidence was found for the formation of CrSx species. The dissociation of H2S on Cr3O4 and Cr2O3 films at room temperature produces a decrease of 0.3–0.8 eV in the work function of the surface and significant binding-energy shifts (0.2–0.6 eV) …

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Intrinsic Chaos In A Dc Field Biased Quantum Heterostructure, A. Jason Mcnary, Ashok Puri Jan 1997

Intrinsic Chaos In A Dc Field Biased Quantum Heterostructure, A. Jason Mcnary, Ashok Puri

Physics Faculty Publications

A closed, quantum, double barrier, GaAs/AlGaAs heterostructure is made chaotic by adding a nonlinear potential term, α〈Q(t)〉, to the time-dependent Schrödinger equation, and the dynamical behavior of an electron cloud moving in the heterostructure biased by a dc electric field is examined numerically. Using phase-space diagrams, power spectrums, and Lyapunov exponents, both qualitative and quantitative measures of the chaos in the system were taken. In general, for all values of α, the nonlinearity parameter, the Lyapunov exponent, λ, increases as the applied dc field, β, increases. However, for values of α ⩽ 1.376, we notice …

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Optical Studies Of Ge Islanding On Si(111), P. D. Persans, P. W. Deelman, K. L. Stokes, L. J. Schowalter, A. Byrne, T. Thundat Jan 1997

Optical Studies Of Ge Islanding On Si(111), P. D. Persans, P. W. Deelman, K. L. Stokes, L. J. Schowalter, A. Byrne, T. Thundat

Physics Faculty Publications

We report an experimental study of the optical properties of island layers resulting from molecular beam epitaxial deposition of Ge on Si(111) substrates. The combination of electroreflectance spectroscopy of the E1 transition and Raman scattering allows us to separately determine the strain and composition of the islands. For deposition at 500 °C a deposited layer of 1.36 nm of Ge assembles into 80 nm diameter islands 11 nm thick. The average Si impurity content in the islands is 2.5% while the average in-plane strain is 0.5%. Both strain and Si impurity content in islands decrease with increasing Ge deposition

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Far-Field Scattering Of A Non-Gaussian Off-Axis Axisymmetric Laser Beam By A Spherical Particle, James A. Lock, Joseph T. Hodges Nov 1996

Far-Field Scattering Of A Non-Gaussian Off-Axis Axisymmetric Laser Beam By A Spherical Particle, James A. Lock, Joseph T. Hodges

Physics Faculty Publications

Experimental laser beam profiles often deviate somewhat from the ideal Gaussian shape of the axisymmetric TEM(00) laser mode. To take these deviations into account when calculating light scattering of an off-axis beam by a spherical particle, we use our phase-modeling method to approximate the beam-shape coefficients in the partial wave expansion of an experimental laser beam. We then use these beam-shape coefficients to compute the near-forward direction scattering of the off-axis beam by the particle. Our results are compared with laboratory data, and we give a physical interpretation of the various features observed in the angular scattering patterns. (C) 1996 …

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Effect Of Multistep Wafer-Annealing On Main Traps In Czochralski-Grown Semi-Insulating Gaas, Z-Q. Fang, David C. Look, H. Yamamoto, H. Shimakura Nov 1996

Effect Of Multistep Wafer-Annealing On Main Traps In Czochralski-Grown Semi-Insulating Gaas, Z-Q. Fang, David C. Look, H. Yamamoto, H. Shimakura

Physics Faculty Publications

Both multistep wafer‐annealed (MWA) and ingot‐annealed semi‐insulating (SI) GaAs wafers, grown by the Czochralski technique, are characterized by using normalized thermally stimulated current (NTSC) spectroscopy. Two main NTSC traps, T3 at 200 K and T5 at 140 K, which are thought to be related to arsenic vacancy defects, are found to be largely suppressed by MWA processes, especially by a new MWA process. Concomitant with a decrease of these traps, a significant increase of the threshold electrical field for both the thermal quenching of T5 and the low‐temperature photocurrent saturation has been observed

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An Exactly Soluble Fresnel Diffraction Model Of Two-Slit Interference, James A. Lock Oct 1996

An Exactly Soluble Fresnel Diffraction Model Of Two-Slit Interference, James A. Lock

Physics Faculty Publications

Using the formalism of Fresnel diffraction, we examine the diffraction and interference of two initially widely separated parallel Gaussian light beams. This two-beam configuration is a version of Young's two-slit interference problem that is free of the mathematical complexity that occurs in most Fresnel diffraction calculations. As a result, it clearly and simply illustrates the transition from ray optics to wave interference. (C) 1996 American Association of Physics Teachers.

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Deep-Center Hopping Conduction In Gan, David C. Look, D. C. Reynolds, W. Kim, Ö. Aktas, A. Botchkarev, A. Salvador, H. Morkoç Sep 1996

Deep-Center Hopping Conduction In Gan, David C. Look, D. C. Reynolds, W. Kim, Ö. Aktas, A. Botchkarev, A. Salvador, H. Morkoç

Physics Faculty Publications

Molecular‐beam‐epitaxial GaN layers change from strongly conductive (ρ≂10−2 Ω cm at 300 K) to semi‐insulating (ρ≂106 Ω cm) as the N flux is increased. Layers grown at low fluxes show strong n‐type conduction, with transport in the conduction band at high temperatures and in a shallow donor band at low temperatures. For layers grown at high N fluxes, the Hall coefficients become too small to measure, suggesting hopping conduction among deep centers. The temperature‐dependent resistivity data are most consistent with multiphonon, rather than single‐phonon, hopping.

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Simple Measurement Of 300 K Electron Capture Cross Section For El2 In Gaas, David C. Look, Z-Q. Fang Sep 1996

Simple Measurement Of 300 K Electron Capture Cross Section For El2 In Gaas, David C. Look, Z-Q. Fang

Physics Faculty Publications

A simple experiment involving only the measurement of dark current Idark and 1.1 μm photocurrent IPC in semi‐insulating (SI) GaAs allows an accurate determination of the electron capture cross section σn for the important defect EL2 in GaAs. For 45 SI GaAs samples, from 12 different boules, grown by three different techniques, we find that IPC/Idark=1.96±0.05 at 300 K. This relationship gives σn=1.4±0.4×10−16 cm2, which is compared to previously estimated values.

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On Hall Scattering Factors For Holes In Gaas, David C. Look, C. E. Stutz, J. R. Sizelove, K. R. Evans Aug 1996

On Hall Scattering Factors For Holes In Gaas, David C. Look, C. E. Stutz, J. R. Sizelove, K. R. Evans

Physics Faculty Publications

Hall scattering factors for electrons and holes in molecular beam epitaxial GaAs layers have been determined by comparing carrier concentrations measured by the Hall effect with those measured by the electrochemical capacitance–voltage technique. The conclusion is that both the electron and hole scattering factors are near unity for n ranging from 2×1016 to 7×1017 cm−3, and p ranging from 5×1016 to 4×1019 cm−3. This conclusion is consistent with the present theory for electrons, but not with that for holes.

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Far-Field Scattering Of An Axisymmetric Laser Beam Of Arbitrary Profile By An On-Axis Spherical Particle, James A. Lock, Joseph T. Hodges Jul 1996

Far-Field Scattering Of An Axisymmetric Laser Beam Of Arbitrary Profile By An On-Axis Spherical Particle, James A. Lock, Joseph T. Hodges

Physics Faculty Publications

Experimental laser beam profiles often deviate somewhat from the ideal Gaussian shape of the TEM(00) laser mode. In order to take these deviations into account when calculating light scattering, we propose a method for approximating the beam shape coefficients in the partial wave expansion of an experimental laser beam. We then compute scattering by a single dielectric spherical particle placed on the beam's axis using this method and compare our results to laboratory data. Our model calculations fit the laboratory data well. (C) 1996 Optical Society of America

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Ground And Excited State Exciton Spectra From Gan Grown By Molecular-Beam Epitaxy, D. C. Reynolds, David C. Look, W. Kim, Ö. Aktas, A. Botchkarev, A. Salvador, H. Morkoç, D. N. Talwar Jul 1996

Ground And Excited State Exciton Spectra From Gan Grown By Molecular-Beam Epitaxy, D. C. Reynolds, David C. Look, W. Kim, Ö. Aktas, A. Botchkarev, A. Salvador, H. Morkoç, D. N. Talwar

Physics Faculty Publications

The emission and reflection spectra of GaN have been investigated in the intrinsic region and the data have been interpreted in terms of the wurtzite crystal band structure. Three intrinsic exciton transitions have been observed, one associated with each of the valence bands. Exciton excited states associated with the two top valence bands were also observed. The exciton binding energies, the band-gap energies, and the exciton Bohr radii are all reported along with the dielectric constant and the spin-orbit and crystal-field parameters for GaN.

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